1994 Volume 80 Issue 8 Pages 629-634
In order to clarify the solidification behavior of semi-solid metals during the initial stage of solidification, a chill block dipping test and numerical analysis have been carried out. The heat transfer between metals and mold and the micro structure near the surface are studied for semi-solid metals of Sn-Pb alloy, Al-Cu alloy, 0.4%C steel and stainless steel. The results obtained in this work are as followes;
1) Thermal resistance between the chill block and the solidified shell of semi-solid metals are the same as that for molten metals. Thus the cooling rates evaluated from the secondary arm spacing are the same in both cases.
2) The shell growth rate of semi-solid metals is larger than that of molten metals because of the decrease of latent heat of fusion. This growth rate is numerically predicted by considering the fraction of solid and the corresponding released latent heat of fusion.
3) The increasing rate of the chill block temperature is small for the casting of semi-solid metals, because the total heat removed from the shell is decreased.
